An object of a hand prosthesis is to reproduce as accurately as possible the appearance and the function of a hand that has had to be replaced. For this purpose, the hand prosthesis should include gripping devices, which may be formed as replicas of fingers, in relation to one another, in order to allow gripping of an object.
US 2003/00195638 A1 discloses a two-finger gripper in which two gripping devices can be displaced from an open position into a closed position, and in which the gripping devices lie directly opposite each other. In this way, an object located between the gripping devices can be held. To release the grip, a reversal of the direction of rotation of the drive can be initiated.
WO 03/017880 A1 discloses a prosthetic hand in which a separate drive is arranged in each individual finger prosthesis, which is mounted on a chassis. With such a prosthetic hand, it is possible to realize different gripping situations, for example fingertip gripping or lateral gripping. Disadvantages are the high degree of control required for each individual finger, the complex technology, with drives integrated in the finger, and increased susceptibility to faults on account of the complex type of construction.